<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
    * {
        margin: 0;
        padding: 0;
    }
    .wrap {
        display: flex;
        width: 600px;
        height: 600px;
        background-color: green;
        align-items: center;
        justify-content: center;
        perspective: 1000px;
    }
    .planet {
        width: 200px;
        height: 200px;
        /* 轨道 */
        border: 2px solid #fff;
        transform-style: preserve-3d;
        position: absolute; /*找到离他最近的position属性不为static元素定位*/
        /* margin: 0 auto;  */
        /* margin-top: 200px; */
        border-radius: 50%;
        /* transform: scaleY(0.5) rotateZ(45deg); */
        animation: planet-rotate 20s linear infinite;
    }
    @keyframes planet-rotate {
        0% {
            transform: rotate(45deg) scaleY(0.5) rotate(0);
        }
        100% {
            transform: rotate(45deg) scaleY(0.5) rotate(360deg);
        }
    }
    .ball {
        width: 50px;
        height: 50px;
        position: absolute;
        border-radius: 50%;
        /* ball 穿过轨道 -25px */
        top: -25px;
        left: calc(50% - 25px);
        background-color: yellowgreen;
        /* transform: rotateZ(-45deg) scaleY(2);  */
        animation: self-rotate 20s linear infinite;
    }
    @keyframes self-rotate {
        0% {
            transform: rotate(0) scaleY(2) rotate(-45deg); 
        }
        100% {
            transform: rotate(-360deg) scaleY(2) rotate(-45deg); 
        }
    }
    </style>
</head>
<body>
    <div class="wrap">
        <!-- 星球 -->
        <div class="planet">
            <div class="ball"></div>
        </div>
    </div>
</body>
</html>